High pressure hoses of rubbery material have been made by sequentially winding alternate layers of a tape of a vulcanisable rubber and of rubber-coated textile fabric and/or metal wire or cord reinforcement on a rotating mandrel, the rubber and reinforcement layers thus laid down be in cross section distinctly laminar in appearance. Such a winding procedure is not only time consuming but it is difficult to apply compact layers of rubber because not much tension can be applied to the easily stretchable tape of unvulcanized rubber.
Moreover, couplings commonly employed on this type of hose comprise an integral outer metal collar and sleeve combination, the sleeve portion of which is built into the internal end bore at each end of the hose section during manufacture. Outer compressive bands or clamps are placed over each end of the hose in the region of the sleeves to assist in retaining the sleeves under internal pressure. Axial forces on the hose are transferred to the couplings and in the existing hose these forces are taken up largely by the outer compression bands. Hose of this construction to be used as dredge discharge sleeves (connector between dredge and floating dredge line) or as floating dredge lines per se require that the internal bore of the sleeves be lined with rubber to resist abrasion. Such lining must be applied by hand in a difficult operation, especially in the smaller hose sizes, at significant expense. Such dredge hoses under favorable service can carry a nominal pressure (burst) rating of 50 to 57 atm. But under unfavorable or severe service conditions, the combination of high internal pressure, and especially of high transient internal pressures exceeding the pressure rating, with twisting, extension and shearing forces exerted at the couplings tend to expel the coupling sleeves. When this happens, dredging must be terminated while the damaged discharged sleeve or hose section is replaced. Also the damaged section usually must be sent back to the manufacturer for repair. Under these conditions the maximum allowable working pressure of the hose may be as low as 20 atm. or less, whereas the hose body can easily be built to withstand much higher pressures.
Floating dredge hoses of rubber are now made having externally applied flotation collars so as to float without the usual pontoon supports. The action of tides, winds and waves on such floating lines often impose very severe strain on the couplings which sometimes fail at an unacceptable rate. These problems plus a tendency for dredging pressures to increase require significantly improved hose incoporating improved couplings.